1. Field of the Invention
The present invention relates to a suturing needle for medical use having an improved bending strength and a reduced piercing resistance.
2. Description of Prior Art
Generally, a suturing needle for medical use is manipulated by a surgeon with a needle holder for clamping the needle, and the needle has a function of piercing an affected part of a body to pass a suture through the affected part. In addition, various kinds of the suturing needles for medical use with different configurations and sizes have been provided, and a suitable needle is selected among the suturing needles for medical use and is used according to the affected part to be sutured.
The suturing needle for medical use has a sharp needle tip at a tip end of the needle and has a needle tip portion formed at a predetermined distance from the needle tip, and the needle tip portion has, in sequence, a body portion and a distal end portion. A thickness of the needle tip portion has gradually increased from the sharp needle tip to the body portion, and each of the suturing needles for medical use has its own cross-sectional configuration. For example, a cross-sectional configuration of a needle tip portion may be polygonal, where a plurality of edges constituting the polygonal configuration form cutting edges; or a cross-sectional configuration may be circular with no cutting edges. The suturing needle for medical use with the cutting edge has a function of piercing a tissue with the needle tip and tearing the tissue; on the other hand, the suturing needle for medical use without the cutting edge has a function of pressingly widening the tissue to which the needle tip has pierced.
The body portion has a cross-sectional configuration extended from the cross section of the needle tip portion, or has a circular cross section, regardless of types of the cross-sectional configuration of the needle tip portion, and also the cross-sectional area of the body portion is constantly maintained. In particular, the suturing needle for medical use which even forms the cutting edge in the needle tip portion has no cutting edge in the body portion. In addition, the distal end portion is a portion to which a suture is coupled, and the distal end portion has a hole defined by a pair of hole supports having a spring property, or a blind hole formed in the distal end surface.
Specific examples of the aforementioned suturing needle for medical use will be explained. For example, a suturing needle for medical use disclosed in Japanese Unexamined Patent Publication (KOKAI) Showa No. 63-257539 is a spatulate suturing needle 51 structured for ophthalmic use as shown in FIG. 4. In the spatulate suturing needle 51, the cross section of a needle tip portion 51a is partially triangle shown in FIG. 4(c) and quadrangle shown in FIG. 4(d), and surfaces 52 constituting each of sides are formed as concave surfaces, and intersection of the above concaved surfaces forms each of ridgelines 53 as being acute. In particular, as for a portion corresponding to a body portion 51b as shown in FIG. 4(e), each of the ridgelines 53 has a highly acute angle of a cutting edge or an angle according to the cutting edge. According to the above spatulate suturing needle 51, since the acute ridgeline 53 passes through the tissue along the portion cut by the edge of the needle tip portion 51a, the portion thus injured can be reduced, and since contacting of the concave surface 52 with the tissue is reduced, the piercing resistance can be lowered.
In addition, a suturing needle 61 for medical use disclosed in Japanese Utility Model Publication (KOKAI) Showa No. 56-61212 is a needle where several convex portions 62 and concave portions 63 are alternately formed from a needle tip portion 61a toward a needle body portion 61b as shown in FIG. 5. In this art, since the convex portions 62 and the concave portions 63 are corresponded with convex portions and concave portions formed in a needle holder (not shown) to be grasped, suturing operation can be made in a stable state.
When an affected part of a human body is to be sutured by the respective suturing needle for medical use as mentioned above, the needle becomes a cantilever bar where the portion to be clamped by the needle holder is served as a supporting portion and the needle tip portion is served as a loading portion, and therefore, a large flexure is produced in the portion clamped by the needle holder, with the result that the suturing operation may suffer. However, the respective suturing needles for medical use as mentioned above do not solve such a problem, and consequently, the idea of reducing the flexure is not disclosed.
It is necessary to improve strength of the material in order to suppress the flexure generated during the suturing operation. However, when the strength of the material is improved, fragility becomes increased, causing derivatively such a problem that the material is easily folded during the suturing operation.